1. Field of the Invention
This invention relates generally to corona ignition assemblies, and methods of manufacturing the corona ignition assemblies.
2. Related Art
Corona discharge ignition systems include a corona igniter assembly typically with a firing end assembly and an ignition coil assembly attached to one another and inserted into a combustion chamber of an engine. The firing end assembly includes a central electrode charged to a high radio frequency voltage potential, creating a strong radio frequency electric field in a combustion chamber. The electric field causes a portion of a mixture of fuel and air in the combustion chamber to ionize and begin dielectric breakdown, facilitating combustion of the fuel-air mixture. The electric field is preferably controlled so that the fuel-air mixture maintains dielectric properties and corona discharge occurs, also referred to as non-thermal plasma. The ionized portion of the fuel-air mixture forms a flame front which then becomes self-sustaining and combusts the remaining portion of the fuel-air mixture. The electric field is also preferably controlled so that the fuel-air mixture does not lose all dielectric properties, which would create a thermal plasma and an electric arc between the electrode and grounded cylinder walls, piston, or other portion of the igniter. Ideally, the field is also controlled so that the corona discharge only forms at the firing end and not along other portions of the corona igniter assembly. However, such control is oftentimes difficult to achieve.